public async Task OnGetAsync(int?id, int?courseID)
{
Instructor = new InstructorIndexData();
Instructor.Instructors = await _context.Instructors
.Include(i => i.OfficeAssignment)
.Include(i => i.CourseAssignments)
.ThenInclude(i => i.Course)
.ThenInclude(i => i.Department)
.OrderBy(i => i.LastName)
.ToListAsync();
if (id != null)
{
InstructorID = id.Value;
Instructor instructor = Instructor.Instructors.Single(i => i.ID == id.Value);
Instructor.Courses = instructor.CourseAssignments.Select(s => s.Course);
InstructorName = instructor.FirstMidName + " " + instructor.LastName;
}
if (courseID != null)
{
CourseID = courseID.Value;
var courses = Instructor.Courses.ToList();
var selectedCourse = courses.Single(x => x.CourseID == courseID);
await _context.Entry(selectedCourse).Collection(x => x.Enrollments).LoadAsync();
foreach (Enrollment enrollment in selectedCourse.Enrollments)
{
await _context.Entry(enrollment).Reference(x => x.Student).LoadAsync();
}
Instructor.Enrollments = selectedCourse.Enrollments;
CourseName = courses.First(course => course.CourseID == courseID).Title;
}
}
public async Task OnGetAsync(int?id, int?courseID)
{
Instructor = new InstructorIndexData();
Instructor.Instructors = await _context.Instructors
.Include(i => i.OfficeAssignment)
.Include(i => i.CourseAssigments)
.ThenInclude(i => i.Course)
.ThenInclude(i => i.Department)
//.Include(i => i.CourseAssigments)
// .ThenInclude(i => i.Course)
// .ThenInclude(i => i.Enrollments)
// .ThenInclude(i => i.Student)
//.AsNoTracking()
.OrderBy(i => i.LastName).ToListAsync();
if (id != null)
{
InstructorID = id.Value;
Instructor instructor = Instructor.Instructors.Where(i => i.ID == id.Value).Single();
Instructor.Courses = instructor.CourseAssigments.Select(s => s.Course);
}
if (courseID != null)
{
CourseID = courseID.Value;
var selectedCourse = Instructor.Courses.Where(x => x.CourseID == courseID).Single(); // this part only includes student info if a course if selected
await _context.Entry(selectedCourse).Collection(x => x.Enrollments).LoadAsync();
foreach (Enrollment enrollment in selectedCourse.Enrollments)
{
await _context.Entry(enrollment).Reference(x => x.Student).LoadAsync();
}
Instructor.Enrollments = selectedCourse.Enrollments;
}
}
public async Task OnGetAsync(int?id, int?courseID)
{
Instructor = new InstructorIndexData();
Instructor.Instructors = await _context.Instructors
.Include(i => i.OfficeAssignment)
.Include(i => i.CourseAssignments)
.ThenInclude(i => i.Course)
.ThenInclude(i => i.Department)
// eager loading of enrollments
//.Include(i => i.CourseAssignments)
// .ThenInclude(i => i.Course)
// .ThenInclude(i => i.Enrollments)
// .ThenInclude(i => i.Student)
//.AsNoTracking()
.OrderBy(i => i.LastName)
.ToListAsync();
if (id != null)
{
InstructorID = id.Value;
//Instructor instructor = Instructor.Instructors.Where(
// i => i.ID == id.Value).Single();
Instructor instructor = Instructor.Instructors.Single(
i => i.ID == id.Value);
Instructor.Courses = instructor.CourseAssignments.Select(s => s.Course);
}
if (courseID != null)
{
CourseID = courseID.Value;
// with eager loading, uncomment this line.
//Instructor.Enrollments = Instructor.Courses.Single(
// x => x.CourseID == courseID).Enrollments;
// explicit loading, only when requested:
var selectedCourse = Instructor.Courses.Where(x => x.CourseID == courseID).Single();
await _context.Entry(selectedCourse).Collection(x => x.Enrollments).LoadAsync();
foreach (Enrollment enrollment in selectedCourse.Enrollments)
{
await _context.Entry(enrollment).Reference(x => x.Student).LoadAsync();
}
Instructor.Enrollments = selectedCourse.Enrollments;
}
}
public async Task OnGetAsync(int?id, int?courseID)
{
Instructor = new InstructorIndexData();
Instructor.Instructors = await _context.Instructors
.Include(i => i.OfficeAssignment)
.Include(i => i.CourseAssignments)
.ThenInclude(i => i.Course)
.ThenInclude(i => i.Department)
// // The current code specifies eager loading for Enrollments and Students:
// .Include(i => i.CourseAssignments)
//.ThenInclude(i => i.Course)
// .ThenInclude(i => i.Enrollments)
// .ThenInclude(i => i.Student)
// //end
// .AsNoTracking()
.OrderBy(i => i.LastName)
.ToListAsync();
if (id != null)
{
InstructorID = id.Value;
Instructor instructor = Instructor.Instructors.Where(
i => i.ID == id.Value).Single();
Instructor.Courses = instructor.CourseAssignments.Select(s => s.Course);
}
if (courseID != null)
{
CourseID = courseID.Value;
//Update the OnGetAsync with the following code:
var selectedCourse = Instructor.Courses.Where(x => x.CourseID == courseID).Single();
await _context.Entry(selectedCourse).Collection(x => x.Enrollments).LoadAsync();
foreach (Enrollment enrollment in selectedCourse.Enrollments)
{
await _context.Entry(enrollment).Reference(x => x.Student).LoadAsync();
}
Instructor.Enrollments = selectedCourse.Enrollments;
//end
}
}
public async Task OnGetAsync(int?id, int?courseID)
{
Instructor = new InstructorIndexData();
Instructor.Instructors = await _context.Instructors.Include(i => i.OfficeAssignment)
.Include(i => i.CourseAssignments)
.ThenInclude(i => i.Course)
.ThenInclude(i => i.Department)
//.Include(i => i.CourseAssignments)
//.ThenInclude(i => i.Course)
//.ThenInclude(i => i.Enrollments)
//.ThenInclude(i => i.Student)
//.AsNoTracking()
.OrderBy(i => i.LastName)
.ToListAsync();
if (id != null)
{
InstructorID = id.Value;
//Instructor instructor = Instructor.Instructors.Where(
// i => i.ID == id.Value).Single(); //get single value of selected instructor
Instructor instructor = Instructor.Instructors.Single(i => i.ID == id.Value);
Instructor.Courses = instructor.CourseAssignments.Select(c => c.Course); //Get a list of courses
}
/*if (courseID != null)
* {
* CourseID = courseID.Value;
* //Instructor.Enrollments = Instructor.Courses.Where(x => x.CourseID == courseID).Single().Enrollments;
* Instructor.Enrollments = Instructor.Courses.Single(x => x.CourseID == courseID).Enrollments;
* //Get enrollments for the seelected course
* }*/
if (courseID != null)
{
var selectedCourse = Instructor.Courses.Where(x => x.CourseID == courseID).Single(); //Single converts from being a list to a single object
await _context.Entry(selectedCourse).Collection(x => x.Enrollments).LoadAsync(); //Loads entities linked to main entity
foreach (Enrollment enrollment in selectedCourse.Enrollments)
{
await _context.Entry(enrollment).Reference(x => x.Student).LoadAsync(); //Loads a single field
}
Instructor.Enrollments = selectedCourse.Enrollments;
}
}
public async Task OnGetAsync(int?id, int?courseID)
{
Instructor = new InstructorIndexData();
Instructor.Instructors = await _context.Instructors
.Include(i => i.OfficeAssignment)
.Include(i => i.CourseAssignments)
.ThenInclude(i => i.Course)
.ThenInclude(i => i.Department)
// упреждающая загрузка для Enrollments и Students:
//.Include(i => i.CourseAssignments)
//.ThenInclude(i => i.Course)
//.ThenInclude(i => i.Enrollments)
//.ThenInclude(i => i.Student)
//.AsNoTracking()
.OrderBy(i => i.LastName)
.ToListAsync();
if (id != null)
{
InstructorID = id.Value;
Instructor instructor = Instructor.Instructors.Where(
i => i.ID == id.Value).Single();
Instructor.Courses = instructor.CourseAssignments.Select(s => s.Course);
// TODO will knock debt
try { Instructor.Enrollments = Instructor.Courses.First().Enrollments; } catch (Exception ignore) {}
}
if (courseID != null)
{
CourseID = courseID.Value;
var selectedCourse = Instructor.Courses.Where(x => x.CourseID == courseID).Single();
await _context.Entry(selectedCourse).Collection(x => x.Enrollments).LoadAsync();
foreach (Enrollment enrollment in selectedCourse.Enrollments)
{
await _context.Entry(enrollment).Reference(x => x.Student).LoadAsync();
}
Instructor.Enrollments = selectedCourse.Enrollments;
}
}
public async Task OnGetAsync(int?id, int?courseID)
{
Instructor = new InstructorIndexData();
Instructor.Instructors = await _context.Instructors
.Include(i => i.OfficeAssignment)
.Include(i => i.CourseAssignments)
.ThenInclude(i => i.Course)
.ThenInclude(i => i.Department)
.Include(i => i.CourseAssignments)
.ThenInclude(ca => ca.Course)
.ThenInclude(c => c.Enrollments)
.ThenInclude(e => e.Student)
.OrderBy(i => i.LastName)
.ToListAsync();
if (id != null)
{
InstructorID = id.Value;
Instructor instructor = Instructor.Instructors
.Where(i => i.ID == id).Single();
Instructor.Courses = instructor.CourseAssignments.Select(c => c.Course);
}
if (courseID != null)
{
CourseID = courseID.Value;
var selectedCourse = Instructor.Courses
.Single(c => c.CourseID == courseID.Value);
await _context.Entry(selectedCourse).Collection(x => x.Enrollments).LoadAsync();
foreach (var enrollment in selectedCourse.Enrollments)
{
await _context.Entry(enrollment).Reference(x => x.Student).LoadAsync();
}
Instructor.Enrollments = selectedCourse.Enrollments;
}
}
public async Task <IActionResult> OnPostAsync(int id)
{
if (!ModelState.IsValid)
{
return(Page());
}
var departmentToUpdate = await _context.Departments.Include(i => i.Administrator).FirstOrDefaultAsync(m => m.DepartmentID == id);
if (departmentToUpdate == null)
{
return(await HandleDeletedDepartment());
}
_context.Entry(departmentToUpdate).Property("RowVersion").OriginalValue = Department.RowVersion;
//The Department.RowVersion is set when the record is read from the database on the initial GET.
//if 2RowVersion2 has been updated so it doesn't match Department.RowVersion then Concurrency exception is thrown.
//OriginalValue is the database value just before we tried to save
if (await TryUpdateModelAsync <Department>(departmentToUpdate, "Department",
s => s.Name, s => s.StartDate, s => s.Budget, s => s.InstructorID))
{
try
{
await _context.SaveChangesAsync();
return(RedirectToPage("./Index"));
}
catch (DbUpdateConcurrencyException ex)
{
var exceptionEntry = ex.Entries.Single();
var clientValues = (Department)exceptionEntry.Entity;
var databaseEntry = exceptionEntry.GetDatabaseValues();
if (databaseEntry == null)
{
ModelState.AddModelError(string.Empty, "Unable to save. The department was deleted by another user");
return(Page());
}
var dbValues = (Department)databaseEntry.ToObject();
await setDbErrorMessage(dbValues, clientValues, _context);
Department.RowVersion = (byte[])dbValues.RowVersion; //sets the rowversion to be the correct one from the database
ModelState.Remove("Department.RowVersion");
}
}
InstructorNameSL = new SelectList(_context.Instructors, "ID", "FullName", departmentToUpdate.InstructorID);
return(Page());
}
public async Task OnGetAsync(int?id, int?courseID)
{
Instructor = new InstructorViewModel();
Instructor.Instructors = await _context.Instructors
.Include(i => i.OfficeAssignment)
.Include(i => i.CourseAssignments)
.ThenInclude(i => i.Course)
.ThenInclude(i => i.Department)
/* .Include(i => i.CourseAssignments)
* .ThenInclude(i => i.Course)
* .ThenInclude(i => i.Enrollments)
* .ThenInclude(i => i.Student)
* .AsNoTracking() */
.OrderBy(i => i.LastName)
.ToListAsync();
if (id != null)
{
InstructorID = id.Value;
Instructor instructor = Instructor.Instructors.Single(
i => i.ID == id.Value); //You can add condition into Select and remove Where
//If you need a single item by condition
Instructor.Courses = instructor.CourseAssignments.Select(s => s.Course);
}
if (courseID != null)
{
CourseID = courseID.Value;
var selectedCourse = Instructor.Courses.Single(x => x.CourseID == courseID);
await _context.Entry(selectedCourse).Collection(x => x.Enrollments).LoadAsync();
foreach (Enrollment enrollment in selectedCourse.Enrollments)
{
await _context.Entry(enrollment).Reference(x => x.Student).LoadAsync();
}
Instructor.Enrollments = selectedCourse.Enrollments;
}
}
public async Task <IActionResult> OnPostAsync(int id)
{
if (!ModelState.IsValid)
{
return(Page());
}
var departmentToUpdate = await _context.Departments
.Include(i => i.Administrator)
.FirstOrDefaultAsync(m => m.DepartmentID == id);
// null means Department was deleted by another user.
if (departmentToUpdate == null)
{
return(await HandleDeletedDepartment());
}
// Update the RowVersion to the value when this entity was
// fetched. If the entity has been updated after it was
// fetched, RowVersion won't match the DB RowVersion and
// a DbUpdateConcurrencyException is thrown.
// A second postback will make them match, unless a new
// concurrency issue happens.
_context.Entry(departmentToUpdate)
.Property("RowVersion").OriginalValue = Department.RowVersion;
if (await TryUpdateModelAsync <Department>(
departmentToUpdate,
"Department",
s => s.Name, s => s.StartDate, s => s.Budget, s => s.InstructorID))
{
try
{
await _context.SaveChangesAsync();
return(RedirectToPage("./Index"));
}
catch (DbUpdateConcurrencyException ex)
{
var exceptionEntry = ex.Entries.Single();
var clientValues = (Department)exceptionEntry.Entity;
var databaseEntry = exceptionEntry.GetDatabaseValues();
if (databaseEntry == null)
{
ModelState.AddModelError(string.Empty, "Unable to save. " +
"The department was deleted by another user.");
return(Page());
}
var dbValues = (Department)databaseEntry.ToObject();
await setDbErrorMessage(dbValues, clientValues, _context);
// Save the current RowVersion so next postback
// matches unless an new concurrency issue happens.
Department.RowVersion = (byte[])dbValues.RowVersion;
// Must clear the model error for the next postback.
ModelState.Remove("Department.RowVersion");
}
}
InstructorNameSL = new SelectList(_context.Instructors,
"ID", "FullName", departmentToUpdate.InstructorID);
return(Page());
}
public void UpdateStudent(Student student)
{
context.Entry(student).State = EntityState.Modified;
}
public async Task <IActionResult> OnPostAsync(int id)
{
if (!ModelState.IsValid)
{
return(Page());
}
var departmentToUpdate = await _context.Departments
.Include(i => i.Administrator)
.FirstOrDefaultAsync(m => m.DepartmentID == id);
// null означает, что отдел был удален другим пользователем.
if (departmentToUpdate == null)
{
return(HandleDeletedDepartment());
}
// Обновляем RowVersion до значения, когда этот объект был
// извлечен. Если объект был обновлен после того, как
// извлечен, RowVersion не будет соответствовать DB RowVersion и
// создается исключение DbUpdateConcurrencyException.
// Department.RowVersion является значением на момент извлечения
// сущности. OriginalValue является значением в базе данных на момент
// вызова FirstOrDefaultAsync в этом методе.
_context.Entry(departmentToUpdate).Property("RowVersion").OriginalValue = Department.RowVersion;
if (await TryUpdateModelAsync(
departmentToUpdate,
"Department",
s => s.Name, s => s.StartDate, s => s.Budget, s => s.InstructorID))
{
try
{
await _context.SaveChangesAsync();
return(RedirectToPage("./Index"));
}
catch (DbUpdateConcurrencyException ex)
{
var exceptionEntry = ex.Entries.Single();
var clientValues = (Department)exceptionEntry.Entity;
var databaseEntry = exceptionEntry.GetDatabaseValues();
if (databaseEntry == null)
{
ModelState.AddModelError(string.Empty, "Unable to save. " +
"The department was deleted by another user.");
return(Page());
}
var dbValues = (Department)databaseEntry.ToObject();
await SetDbErrorMessage(dbValues, clientValues, _context);
// Сохраняем текущий RowVersion
Department.RowVersion = (byte[])dbValues.RowVersion;
// Необходимо очистить ошибку модели для следующего постбэка.
ModelState.Remove("Department.RowVersion");
}
}
InstructorNameSL = new SelectList(_context.Instructors,
"ID", "FullName", departmentToUpdate.InstructorID);
return(Page());
}
public async Task <IActionResult> Edit(int?id, byte[] rowVersion)
{
if (id == null)
{
return(NotFound());
}
var departmentToUpdate = await _context.Departments
.Include(i => i.Administrator)
.SingleOrDefaultAsync(m => m.DepartmentID == id);
if (departmentToUpdate == null)
{
Department deleteDepartment = new Department();
await TryUpdateModelAsync(deleteDepartment);
ModelState.AddModelError(string.Empty,
"Unable to save changes, The department was deleted by another user."
);
ViewData["InstructorID"] = new SelectList(_context.Instructors, "ID", "FullName", deleteDepartment.InstructorID);
return(View(deleteDepartment));
}
_context.Entry(departmentToUpdate).Property("RowVersion").OriginalValue = rowVersion;
if (await TryUpdateModelAsync <Department>(
departmentToUpdate,
"",
s => s.Name, s => s.StartDate, s => s.Budget, s => s.InstructorID
))
{
try
{
await _context.SaveChangesAsync();
return(RedirectToAction(nameof(Index)));
}
catch (DbUpdateConcurrencyException ex)
{
var exceptionEntry = ex.Entries.Single();
var clientValues = (Department)exceptionEntry.Entity;
var databaseEntry = exceptionEntry.GetDatabaseValues();
if (databaseEntry == null)
{
ModelState.AddModelError(string.Empty,
"Unable to save changes, The department was deleted by another user.");
}
else
{
var databaseValues = (Department)databaseEntry.ToObject();
if (databaseValues.Name != clientValues.Name)
{
ModelState.AddModelError("Name", $"Curent value:{databaseValues.Name}");
}
if (databaseValues.Budget != clientValues.Budget)
{
ModelState.AddModelError("Budget", $"Current value: {databaseValues.Budget}");
}
if (databaseValues.StartDate != clientValues.StartDate)
{
ModelState.AddModelError("StartDate", $"Current Value: {databaseValues.StartDate}");
}
if (databaseValues.InstructorID != clientValues.InstructorID)
{
Instructor databaseInstructor = await _context.Instructors.SingleOrDefaultAsync(i => i.ID == databaseValues.InstructorID);
ModelState.AddModelError("InstructorID", $"Current value:{databaseInstructor?.FullName}");
}
ModelState.AddModelError(string.Empty, "The record you attempted to edit "
+ "was modified by another user after you got the orginal value. The"
+ "edit operation was canceled and the current values in the database"
+ "have been displayed. If you still want to edit this record, click"
+ "the Save button agin. Otherwise click the Back to List hyperlink");
departmentToUpdate.RowVersion = (byte [])databaseValues.RowVersion;
ModelState.Remove("RowVersion");
}
}
}
ViewData["InstructorID"] = new SelectList(_context.Instructors, "ID", "FullName", departmentToUpdate.InstructorID);
return(View(departmentToUpdate));
}
